Preparation Of Bio-Based Intumescent Flame Retardant And Its Application In Fire Retardant Coatings For Steel Structures

The steel structure material widely used in modern buildings,but the fire is very easy to make it collapsed,seriously affected people's life and property safety.Fire retardant coatings are usually used to slow down the temperature rise of steel structures,prolong the fire resistance time and strive for more chances to escape.Traditional intumescent fire retardant coatings have high flame retardant efficiency,but it is easy to migrate to the polymer surface,resulting in the failure of the fire retardant;at the same time,the poor stability and poor compatibility with polymer also limit its application in coatings.It is a general trend to study the intumescent flame retardant which has good compatibility with matrix,high thermal stability,and integrated carbon source,acid source and gas source.It will guide the development of flame retardant in the further.In this paper,the raw materials were screened reasonably which based on the existing scientific research,and the new flame retardant molecules were designed by molecular design,and applied it to fire retardant coatings to study its application performance.The selected "carbon source" was a bio-based material,environmentally friendly,inexpensive,and widely available;The selected "acid source" was PEPA with high phosphorus content which has the advantages of smoke suppression and carbon residue increase;"Gas source" bonded the above two and prepared the bio-based intumescent flame retardant with these three sources.Fill it with different proportion into the water-based epoxy resin coating.The coating was sprayed onto the surface of Q235 A steel substrate by the spraying technology.The fire retardant coatings were analyzed by thermogravimetric analysis(TG),oxygen index test(LOI),residual carbon scanning(SEM)analysis,large plate combustion test,salt spray test and adhesion test.The results showed that the bio-base flame retardant improved the charring and flame retardancy of the epoxy coating: the carbon content is increased,the limiting oxygen index is more than 25.5%,the dense carbon residue layer is generated,and the fire endurance time is longer.There's no obvious effect on the corrosion resistance and adhesion strength of the coatings with 10wt% flame retardant.